Electrical apparatus



Nov. 1, 1938. R. "r. ZWACK ELECTRIGAL APPARATUS Filed Nov. 5, 1935 INVENTQR. Ray/27000 ZZwac/t B ORN Patented Nov. 1, 1938" 2,135,435

UNITED STATES PATENT OFFICE amc'rmcar. APPARATUS Raymond T. Zwack, East Orange, N. 1., assignor to Eclipse Aviation Corporation, East Orange, N. 1., a corporation of New Jersey 7 Application November 5,1935, Serial No. 48,424

6 Claims. (01.200-161) This invention relates to electrical apparatus, and particularly to the control of the, electrical phenomena incidental tothe interruption of current flow in a closed circuit.

fore they efiect such contact (through slot 20) immediately upon withdrawal of cams IS in the manner above indicated. A suitable spring 24 is provided to resist withdrawal of the cams l3, the spring being mounted within a sleeve 29 .switch, is just sufficient to bring slot 20 opposite '5 In installations of electrical equipment in airplaced in tongued slot 26 in the plate 9, and craft, every current carrying device involving a abutting at its opposite ends on washers 21 and circuit interrupter orswitchis a source 01 pos- 28. The casing sections 5, 6 have radial projecsible interference with the perfect reception and tions 3|, 32' to receive connections to the intransmission of radio signals, as wellas being sulated terminals 34 of the fingers II and I2,

a source of dangerous arcing of current across 'respecthrely. These projections 3|, 32 are shown 10 conducting members on every occasion of interas threaded to receive the threaded coupling nuts, ruption of current flow. It is therefore desirable not shown, of the sheathed conduits in which the to eliminate both these objections wherever posconducting cables or leads are preferably ensible, as for example, in the construction and cased to complete the radio frequency oscillal5 installation of ordinary circuit controlling tion suppressing, or shielding circuit to ground.

' switches. This exterior grounding circuit includes, of course, The object of this invention is to provide an the plate 9 and casing sections 5 and 6, and due improved construction and method of control of to the proximity of the latter to the high portions the operation of a circuit breaker intended for 36, 31 of the fingers ll, l2, there is an opportunity 'use in aircraft operating equipment, suchias igfor absorption of an electrostatic charge in the 20 nition circuits, or in any other location wherein said casing during the breaking of the circuit as it is desired to eliminate either of the sources the fingers move outward from plate 9 to the posiof trouble above outlined. tion shown. Thus the casing is not only an oscil- In the drawing there is illustrated one emlation suppressor but also, in effect, a condenser 5 bodiment of the invention, but it is to be underor capacitor during the breaking away of the stood that the drawing is for the purpose of illusfingers from the plate, and thus reduces the arc tration only and is not to be construed as a ing hazard, as between the said fingers and limitation of the scope of the invention, reference plate, as well as serving to suppress any radio being had for this purpose to the appended claims. frequency oscillations which may subsequently Referring to the drawing: I succeed in passing through the plate 9. It will be Fig. 1 is a longitudinal sectional view of a noted, however, that plate 9 is, in itself, a pracdevice embodying the invention; tically perfect barrier to such oscillations, since Fig. 2 is a longitudinal sectional view at right it extends completely across the area between the angles to the viewpoint of Fig. 1 (along line fingers II and I? when the latter are in open 2-2 of Fig. 1); and circuit position, and thus substantially eliminates 35 Fig. 3 is a transverse sectional view along line any p v capacitance Value across the Said 3-3 of i. fingers; but if an even greater degree of perfec- Reference characters 5 and 6 designate the tion in the matter of radio interference supprestwo major casing sections which, when joined sion is desired, means may be employed to keep 40 as indicated at l and 8, coact with the enclosed the slot 2!! closed while the switch is in the open 4o current conducting, fiat plate 9 to form an elecposition. As shown in Fig. 3 such means may trostatic shield for a pair of current conducting take the form of a pair of grounded supplemental fingers H, i2 adapted to be moved transversely shields 46, M whose outer ends abut cams it in relation to the plate and casing, into the poslwhen the fingers ii, i2 are separated, but are a 5 tion indicated in Fig. 1, and heldin such position spaced from said fingers in both the engaged by the non-conducting cams l3 of the plate until and disengaged position of the fingers. In order such time as the cams are withdrawn by a pull to improve the condenser effect oiv the fingers exerted on the outer end l6 of the plate, the said with respect l casing 5, the latte?! I outer end being designed for attachment of an .may be equipped with thin sheets 60 and Si oi.

operating member engageable with hole l'l. suitable dielectric material such as mica or some Bil Fingers H, 12 are held .in, and insulated from, organic insulating paper similar to that used in mounting screws 2|, 22, respectively, and are of commercial condensers. I suificient resiliency to have a constant tendency It is to be understood that the outward moveto snap into contact with each other, and therement of plate 9, when it is desired to close the the ends of the fingers II and i2 whereupon said fingers may contact with each other through the said slot. The shielding pieces 40 and 4|, being .fastened to the casing act as stationary guides for the plate during such movement.

What is claimed is:

1. In a device of the class described, a metallic casing, a pair of terminals within the casing, a pair of contact fingers movable transversely within the casing to make or break the circuit between said terminals, means for controlling the direction of passage of oscillating current of radio frequency from said fingers when in the open circuit position, said last named means including a metallic plate and cooperating metallic shielding members constituting a continuous grounded shield interposed between said fingers in the open position thereof said plate being apertured to enable said fingers to contact with one another upon movement of the plate suf-- ficiently to bring said apertured portion intothe path of said fingers, whereby the plate itself remains out of contact therewith, means for insulating said fingers from said metallic casing, and means for moving and holding said fingers in positions spaced apart from said plate, and on opposite sides thereof.

2. In a device of the class described, a metallic casing, a pair ofterminals within the casing, a pair of contact fingers movable transversely within the casing to make or break the circuit between said terminals, means for controlling the direction of passage of oscillating current of radio frequency from said fingers when in the open circuit position, said last named means including a metallic plate and cooperating metallic shielding members constituting a continuous grounded shield interposed between said fingers in the open position thereof said plate being apertured to enable said fingers to contact with one another upon movement of the plate sufficiently to bring said apertured portion into the path or said fingers whereby the metal of said plate remains out of contact with said fingers, said apertured portion being covered by said shielding means when said contact fingers are in the open circuit position, means for insulating said fingers from said metallic casing, and means for moving and holding said. fingers in positions spaced apart from said plate, and on opposite sides thereof.

3. In a device or the class described, a metallic casing having a pair of radial projections, a pair of terminals to receive current conductors extending through said radial projections, a pair of contact fingers having end portions movable transversely within the-casing to complete a circuit between saidterminals, and also having intermediate portions movable transversely into close proximity with said casing to by-pass a component of the current in said circuit into said casing upon interruption of current flow between said terminals, means for moving and holding said fingers in the open-circuit position,

- and means for withdrawing said holding means cuit into said casing upon interruption of current flow between said terminals, means for moving and holding said fingers in the opencircuit position, and means for withdrawing said holding means to enable said fingers to move into circuit completing position.

5. In a device oi! the class described, a metal lic casing having a pair or radial projections, a pair of terminals to receive current conductors extending through said radial projections, a pair of contact fingers having end portions movable transversely within the casing to complete a circuit between said terminals, and also having intermediate portions movable transversely into close proximity with said casing to by-pass a component of the current in said circuit into said casing upon interruption of current fiow between said terminals said casing also constituting a shield to suppress electrically produced oscillations of radio frequency, means for moving and holding said fingers in the open-circuit position, and means for withdrawing said holding means to enable said fingers to move into circuit completing position.

6. In a device or the class described, a metallic casing, a pair of terminals within the casing, a pair of contact fingers having end portions movable transversely within the casing to complete a circuit between said terminals, and also having intermediate portions movable transversely into close proximity with said casing to by-pass a component of the current in said circuit into said casing upon interruption of current flow between said terminals said casing also constituting a shield to suppress electrically produced oscillations of radio frequency, means for moving and holding said fingers in the openclrcuit position, and means for withdrawing said holding means to enable said fingers to move into circuit completing position.

- RAYMOND T. ZWACK. 

